Where is the common-sense button that aligns curve handles and resets them?
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A Select all
V V Convert control points to Vector


With just 2 points, this will produce the straight line I think you're looking for? I do this to every Bezier curve on creation..  it just helps get off to a known, 'neutral' start.

After that, you might want to W S subdivide, (or, in 2.8 right click > Subdivide) to make more in-line vertices.